DatabaseError: current transaction is aborted, com

Question

I got a lot of errors with the message :

"DatabaseError: current transaction is aborted, commands ignored until end of transaction block"

after changed from python-psycopg to python-psycopg2 as Django project's database engine.

The code remains the same, just dont know where those errors are from.

Answer 1

In my experience, these errors happen this way:

try:
    code_that_executes_bad_query()
    # transaction on DB is now bad
except:
    pass

# transaction on db is still bad
code_that_executes_working_query() # raises transaction error

There nothing wrong with the second query, but since the real error was caught, the second query is the one that raises the (much less informative) error.

edit: this only happens if the except clause catches IntegrityError (or any other low level database exception), If you catch something like DoesNotExist this error will not come up, because DoesNotExist does not corrupt the transaction.

The lesson here is don't do try/except/pass.

Answer 2

I just had this error too but it was masking another more relevant error message where the code was trying to store a 125 characters string in a 100 characters column:

DatabaseError: value too long for type character varying(100)

I had to debug through the code for the above message to show up, otherwise it displays

DatabaseError: current transaction is aborted

Answer 3

This is very strange behavior for me. I'm surprised that no one thought of savepoints. In my code failing query was expected behavior:

from django.db import transaction
@transaction.commit_on_success
def update():
    skipped = 0
    for old_model in OldModel.objects.all():
        try:
            Model.objects.create(
                group_id=old_model.group_uuid,
                file_id=old_model.file_uuid,
            )
        except IntegrityError:
            skipped += 1
    return skipped

I have changed code this way to use savepoints:

from django.db import transaction
@transaction.commit_on_success
def update():
    skipped = 0
    sid = transaction.savepoint()
    for old_model in OldModel.objects.all():
        try:
            Model.objects.create(
                group_id=old_model.group_uuid,
                file_id=old_model.file_uuid,
            )
        except IntegrityError:
            skipped += 1
            transaction.savepoint_rollback(sid)
        else:
            transaction.savepoint_commit(sid)
    return skipped

Answer 4

In response to @priestc and @Sebastian, what if you do something like this?

try:
    conn.commit()
except:
    pass

cursor.execute( sql )
try: 
    return cursor.fetchall()
except: 
    conn.commit()
    return None

I just tried this code and it seems to work, failing silently without having to care about any possible errors, and working when the query is good.